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14a00470 YQ |
1 | /* Notification to GDB. |
2 | Copyright (C) 1989, 1993-1995, 1997-2000, 2002-2012 Free Software | |
3 | Foundation, Inc. | |
4 | ||
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | /* Async notifications to GDB. When the state of remote target is | |
21 | changed or something interesting to GDB happened, async | |
22 | notifications are used to tell GDB. | |
23 | ||
24 | Each type of notification is represented by an object | |
25 | 'struct notif_server', in which there is a queue for events to GDB | |
26 | represented by 'struct notif_event'. GDBserver writes (by means of | |
27 | 'write' field) each event in the queue into the buffer and send the | |
28 | contents in buffer to GDB. The contents in buffer is specified in | |
29 | RSP. See more in the comments to field 'queue' of | |
30 | 'struct notif_server'. | |
31 | ||
32 | Here is the workflow of sending events and managing queue: | |
33 | 1. At any time, when something interesting FOO happens, a object | |
34 | of 'struct notif_event' or its sub-class EVENT is created for FOO. | |
35 | ||
36 | 2. Enque EVENT to the 'queue' field of 'struct notif_server' for | |
37 | FOO and send corresponding notification packet to GDB if EVENT is | |
38 | the first one. | |
39 | #1 and #2 are done by function 'notif_push'. | |
40 | ||
41 | 3. EVENT is not deque'ed until the ack of FOO from GDB arrives. | |
42 | Before ack of FOO arrives, FOO happens again, a new object of | |
43 | EVENT is created and enque EVENT silently. | |
44 | Once GDB has a chance to ack to FOO, it sends an ack to GDBserver, | |
45 | and GDBserver repeatedly sends events to GDB and gets ack of FOO, | |
46 | until queue is empty. Then, GDBserver sends 'OK' to GDB that all | |
47 | queued notification events are done. | |
48 | ||
49 | # 3 is done by function 'handle_notif_ack'. */ | |
50 | ||
51 | #include "notif.h" | |
52 | ||
53 | static struct notif_server *notifs[] = | |
54 | { | |
55 | ¬if_stop, | |
56 | }; | |
57 | ||
58 | /* Write another event or an OK, if there are no more left, to | |
59 | OWN_BUF. */ | |
60 | ||
61 | void | |
62 | notif_write_event (struct notif_server *notif, char *own_buf) | |
63 | { | |
64 | if (!QUEUE_is_empty (notif_event_p, notif->queue)) | |
65 | { | |
66 | struct notif_event *event | |
67 | = QUEUE_peek (notif_event_p, notif->queue); | |
68 | ||
69 | notif->write (event, own_buf); | |
70 | } | |
71 | else | |
72 | write_ok (own_buf); | |
73 | } | |
74 | ||
75 | /* Handle the ack in buffer OWN_BUF,and packet length is PACKET_LEN. | |
76 | Return 1 if the ack is handled, and return 0 if the contents | |
77 | in OWN_BUF is not a ack. */ | |
78 | ||
79 | int | |
80 | handle_notif_ack (char *own_buf, int packet_len) | |
81 | { | |
82 | int i = 0; | |
83 | struct notif_server *np = NULL; | |
84 | ||
85 | for (i = 0; i < ARRAY_SIZE (notifs); i++) | |
86 | { | |
87 | np = notifs[i]; | |
88 | if (strncmp (own_buf, np->ack_name, strlen (np->ack_name)) == 0 | |
89 | && packet_len == strlen (np->ack_name)) | |
90 | break; | |
91 | } | |
92 | ||
93 | if (np == NULL) | |
94 | return 0; | |
95 | ||
96 | /* If we're waiting for GDB to acknowledge a pending event, | |
97 | consider that done. */ | |
98 | if (!QUEUE_is_empty (notif_event_p, np->queue)) | |
99 | { | |
100 | struct notif_event *head | |
101 | = QUEUE_deque (notif_event_p, np->queue); | |
102 | ||
103 | if (remote_debug) | |
104 | fprintf (stderr, "%s: acking %d\n", np->ack_name, | |
105 | QUEUE_length (notif_event_p, np->queue)); | |
106 | ||
107 | xfree (head); | |
108 | } | |
109 | ||
110 | notif_write_event (np, own_buf); | |
111 | ||
112 | return 1; | |
113 | } | |
114 | ||
115 | /* Put EVENT to the queue of NOTIF. */ | |
116 | ||
117 | void | |
118 | notif_event_enque (struct notif_server *notif, | |
119 | struct notif_event *event) | |
120 | { | |
121 | QUEUE_enque (notif_event_p, notif->queue, event); | |
122 | ||
123 | if (remote_debug) | |
124 | fprintf (stderr, "pending events: %s %d\n", notif->notif_name, | |
125 | QUEUE_length (notif_event_p, notif->queue)); | |
126 | ||
127 | } | |
128 | ||
129 | /* Push one event NEW_EVENT of notification NP into NP->queue. */ | |
130 | ||
131 | void | |
132 | notif_push (struct notif_server *np, struct notif_event *new_event) | |
133 | { | |
134 | int is_first_event = QUEUE_is_empty (notif_event_p, np->queue); | |
135 | ||
136 | /* Something interesting. Tell GDB about it. */ | |
137 | notif_event_enque (np, new_event); | |
138 | ||
139 | /* If this is the first stop reply in the queue, then inform GDB | |
140 | about it, by sending a corresponding notification. */ | |
141 | if (is_first_event) | |
142 | { | |
143 | char buf[PBUFSIZ]; | |
144 | char *p = buf; | |
145 | ||
146 | xsnprintf (p, PBUFSIZ, "%s:", np->notif_name); | |
147 | p += strlen (p); | |
148 | ||
149 | np->write (new_event, p); | |
150 | putpkt_notif (buf); | |
151 | } | |
152 | } | |
153 | ||
154 | static void | |
155 | notif_event_xfree (struct notif_event *event) | |
156 | { | |
157 | xfree (event); | |
158 | } | |
159 | ||
160 | void | |
161 | initialize_notif (void) | |
162 | { | |
163 | int i = 0; | |
164 | ||
165 | for (i = 0; i < ARRAY_SIZE (notifs); i++) | |
166 | notifs[i]->queue | |
167 | = QUEUE_alloc (notif_event_p, notif_event_xfree); | |
168 | } |